[RF] Fix some memory leaks in the RooLagrangianMorphFunc
[RF] Fix some memory leaks in the RooLagrangianMorphFunc

In the previous commit, it was noted that the elements contained by the
`_diagrams` and `_flags` members are leaking.

There are more memory leaks in this class that has also many other
flaws, and a separate issue will be opened to remind the creators of the
RooLagrangianMorphFunc to fix these.

olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root